1. Technical Field
The present invention relates to an occupant protection devices that protect an occupant in a vehicle, such as an automobile.
2. Related Art
A seatbelt module and airbag modules are employed for an occupant protection device (see Japanese Unexamined Patent Application Publication (JP-A) Nos. 2011-213195 and 2005-067273). The seatbelt module is used for restraining an occupant seated in a seat of the vehicle to the seat. The airbag modules are used for expanding an airbag between a structural object such as the steering wheel, instrument panel, or side panel of the vehicle, and the occupant so as to prevent the upper body of the occupant, such as the head, from beating against the structural object.
The airbag modules include an airbag module for the lower legs of an occupant. The airbag module for lower legs according to JP-A No. 2011-213195 expands from the instrument panel to the below-knee portions of the occupant seated in the seat of the vehicle. The airbag module for lower legs expands, which prevents the below-knee portions (lower legs) of the occupant from moving forward at the time of a collision. Thus, the below-knee portions of the occupant are not in contact with the instrument panel. Impact to the lower legs in the case that the below-knee portions of the occupant move to a position which is in contact with the instrument panel can be suppressed.
Collision experiments using crash test dummies have shown that such an occupant protection device very effectively suppresses bodily damage at the time of a collision. However, there has been demand for further improvement in occupant protection devices.
For example, even if the airbag module for lower legs has been expanded at the time of a collision, there remains space at the feet on the lower side of the airbag module for lower legs where the expanded airbag module does not reach. The lower legs of the occupant may move forward through the space at the feet. Also, the position of the upper body of the occupant may drop lower from the seated position before the collision, due to the lower leas of the occupant moving forward from the seated position before the collision.
Thus, although the occupant protection devices yield fairly high occupant protection effects, there has been demand for occupant protection devices having more exact occupant protection effects.